Internal-combustion engine



Oct. 11. 1927.

. 3,644,73l c'. F. KETTERING ET AL, v

INTERNAL COMBUSTION ENGINE Filed April 17', 1922 l5 Sheets-Sheet 4Il.

@et u 27 c. F. KETTERING ET AL INTERNAL CQMBUSTION ENGINE Filed April1'?, 1922 13 sheets-sheet 2 Y 1,644 731 Oct' 11 1927' c. F. KETTERING ETAL INTERNAL COMBUSTION ENGINE Filed April 17, 1922 13 Sheets-Sheetl 3'hun' 1 644 731` Oct' 111927', c. F. KETTERING ET AL INTERNAL COMBUSTIONENGINE 15 sheets-sheet 4 Filed April 17, 1922 A oct. 1,1. 1927.

15 Sheets-Sheet 5.

Filed April l'7 1922 Oct. 11 1927.

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Oct.

11 1927 c. F. KETTERmc;` ETAL INTERNAL COMBUSTION ENGINE Y Filed April17, 1922v l/ '15 sheets-sheet-9 Oct.- 11,1927.

C. F. KETTERING ET AL INTERNAL COMBUSTION ENGINE Filed April 17, 1922 13Sheets-Sheet l0 1,644,731 C. F. KETTERING ET AL Oct. 11, 1927.

INTERNAL COMBUSTION' ENGINE Filed April 51'r, 1922 15 Sheets-Sheet 1lOct. -11, 1927.

c. F. Kr-:T'TERING ET AL INTERNAL COMBUSTION ENGINE Filed April 17, 1922JM. fm/

' y n 44 Oct El 1927' c. F. KETa- ERING ET A L "6 97E/ INTERNALCOMBUSTION ENGINE med April 1v. 1922 15 sheets-sheet 13 Mine/5555 mPatented Oct. l1, 1927.

UNET

(QHiRfl'alilSi F. KETTERING'AND CHARLES 17..k SHORT, OF`DAYTO-N,

GENERAL MOTORS RESEARCH CORPORATION,

DELAWARE.

anni

raar -riica omo,` AssmNons'ro p or DAYTON, OHIO,f A CORPORATION FIN'rammen-.coinBUsTIoNl ENG-INE.

Application mea'Aprn 17', v1922. p semi No. y 553,938.

This invention relates to internal combustion engines and its principalobjects arel the draft tube removed; y Fig. 2 is a right side elevationthereof; Fig. 3v is a left side elevation;

Fig. 4 is a front end elevation of the power 20 unit with the front endportion of the hood removed;'

Fig. 5 isa transverse sectional view ofthe a power unit takensubstantially on the lrne 5-5 of Fig. 1;"

Fig; 6 is asectional ,v .i'ew taken substantially on the linel GF6 ofFig. 3 and'show' ing a portionof the valve operating mechf anism;

Fig. 7 isy a sideview of the ignition unit showing a portion -of the'crank'ca'se Vand driving mechanism for the unit in section, being-takensubstantially on the i the Section line 74-'7 of Fig. 3; l

Fig.' 8 is a top view. of an engine cylinder;

Fig. 9 is a side elevation thereof; Fig. 10 is a sectional view taken-,line 10--10 of Fig. 8;

Fig. 11 is a bottom 'viewof the engine i cylinder;

Fig. 12 is a superstructures Fig. 13 is a side elevation of an enginesuper# structure mounted upon twov adjacent engine cylinders, `(the finsare not shown) certain parts of the superstructure and cylinder beingshown in section, the section vbeing taken on the line 13-13 of Fig. 12;

Fig. 14 is a fragmentary sectional view' takenon the line 14-14 ofFig.12;

Figs. 15 and 16' are plan and sideviews, respectively, of aspring cup;

present inventionl with the hood and top of y plan view of one-of theengine y Fig. 17 is an end elevationshowing a' superstructure and one ofthe engine cyliny ders, the fins on `the cylinder being omitted; Fig. 18is a perspective View showing a pair of engine cylinders to which thesuperstructure is attached `and showing parts of the valve mechanism;

Fig. 19 is a longitudinal sectional View of the vfan mechanism, thefront engine cylinder being shown in side elevation;

Fig. 2U is a transverse sectional View of the fan taken on the line20-20 of Fig. 19;

Fig, 21 is"aplan view of4 one of the fan blades;

, Fig.. 22 Ais a plan view of the draft tube assembly;

Fig. 23 is a left side elevation thereof;

Fig. 24 is a front end View thereof;

Fig. 25 is a view similar to Fig. 24 but showing.' the 'hinged portionof the draft tube in partly open position ig. 26 is a rear endelevationof the draft tu e;

Fig. V27 is a longitudinal sectional view-of the draft tube taken on theline 274-27 of` Fig. 23;

Fig. 28 is a plan View of vthewire mani'-v fold forming a .part of thedraft tube;

' Fig. 29 is a. partial transverse sectional view of the draft tubetaken on the line 294-29 of Fig. 22 on an enlarged scale;l

Fig. 30 is a plan view of the engine, the i engine hood being shown insection;

- Fig. 31 is a left side elevation of the power.

unit with the hood shownpartly inside ele-l vation and partly 1nsection, certain parts of the engine being shownins'ection in order toshow the engine cooling system.

I @trod/mation.

' i The engine-illustrated in the drawings is' designated as a whole bythe numeral 200.v and in the description` which'follows. this power unitis describedl as comprising several organisms which 'cooperate to form arelatively simple and ei'icient mechanism having-advantages which shallappear hereinafter. the engine mechanism the descriptionl thereof, sofar as the same is described herein and- To facilitate anu'nderstanding'of claimed in this present application, is vided into thefollowing parts Crankcas general construction, Cylinder construction andvalve mechanism, and Cooling system.

Crank ycurse general Constr/motion.-

. A crank case construction is Vprovided which isrelativelylight,maintains alignment of the different engine parts andrcan be`manufactured at relatively low cost. These results are `obtained by soforming the parts that a one piece supporting member or engine framevmay be employed as the upper housing member, and the power unit may bedisassembled by removing separately relatively light and substantiallycomplete clutch and transmission units. The forming of the upper andlower housing members for the clutch and gear, mechanisms, so thesemembers may beseparated along the axes of the main shafts,assi stsmaterially in obtaining these results.` The construction however `is notwholly limited to the use of ,a one piece supporting member for all theparts.

. The power unit` (see particularly Figs. 1, 2, and 3) includes a onepiece main sup-- porting member in the form of a. crank case 200extending substantiallythe vfull length of the power unit and'comprising an i'ntlegral tim-ing gear housing 202, crank shafthousing'203, liywheel housing 204:, and a. housing 205 forming the upperhalf of they transmission case. Crankcase 200 is provided with laterallyextending supports or 'arms 2 06 and207 which rest upon spring brackets.208 and 209, respectively. vThese spring brackets are a part of theautomobile chassis described and claimed in the copending application ofCharles F. Kettering and Charles R. Short, Serial No. 553,075, filedApril 15, 1922. vTiming gear housing-202 .is closed ,byv timing gearhousing cover 210 provided at its lower-end with a forwardly extendingPAcylindrical engine 'support 211 which projects into a holeprovidediinfront cr'oss member 212- connecting side frame.

y members 213 and 2111. Members 206, 207

co" i. 218 ofthe change spe-ed ,gear or transmission and 211 form athree point support for the pow-er unit. This construction provides.for-il `wardly projecting frame members secured.

to the main chassis frame and is particularly adapted for air cooledengines, because of their light weight. The centerof gravity of thepower unit is close to the lateral en-l gine supports 208 and 209. Crankcase 200 supports oil pan 215 secured to the crank case byjmeans ofvbolts 216 and n'uts A217.y Crank case 200 supports the lower portion.

. housing which lower portion cooperates with and portion 203 of thecrank case form lau the crank case portion 205 to provide an4enclosurefor the change `speed mechanism.. The oil pan 215, fron't'wallof gear box 218,

enclosure for thefclrank. shaft, cam shaft v and` other .mechanismfconnected therewith. Ug/ Zf'nftter construction .wird calcemechants/1.771,1

Crank case 200 supports six cylinders arranged in pairs, each .palrconsisting ot cylinders 220 and 221. One of the cylinders 221`is shownin detail in Figs. 8 to 11 i11- clusive. The cylinder'221 includes. aAh0ri Zontal base portion 222, a relatively'thin'.

vertical shell portion 223 and a thickerhead portion 224 (Fig. l0). Thebase portion 222 is formed with openings 225 to receivevalve lifterguide bushings 226, and'with holes 227 through which bolts 228 Acarryingnuts 229 may extend for securing the cylinder to the crank case. Thebolts 228 are provided with a knurled portion? 230`which has a press-edfit inthe crank case to retainl the bolts in position when. the nuts2,29 areV removed. l 231 is an endless groove tapered in cross-sectionin the lower faceof the base to receive av resilient packing washer `232(formed of felt or oil resisting cement coated rubber tubing) to renderthe joint between i the cylinder base andcrank case oiltight. Eachcylinder base is formed with two 'similar parallel. bosses 233,l 233projecting fromione side of the cylinder. One of the' bosses 233 isapertu'red'to receive a bolt 228.

When all ofthe cylinders vare located upon the crank case, these bosses233 and' 233 will be arranged in airs. By this construe? tion all of thecylin ers may be castor otherwise formed. alike and a hole. 227 bored inbut one of the -bosseson each cylinder thus reducing the cost ofmanufacture. A clamp v234 (Fig. 2) bearsdownwardly 'against adja-`'centsolidbosses 233 and is secured in posi.-

tion by means of a bolt 235 andya nut 236,

the bolt' 235 having a press lit in the crank,.- case after the y.mannerof the b0lt228.` A.

single bolt 228, is employed'to tie ,the opposite side each cylinder tothe crank case. The cyllnder shell 223A has a' cylindrical outer surfacetogwhich are attached a iplural" l ity of fin loops'237 which -arepreferably Constructed .0f a' continuous strip of 'thin 1"15 relativelypure copper or other material-of highhea't conductivity. The method andapparatus for ,constructing these 'fins are described and `claimedinULS. Letters Patl ent, No. 1,507,318. issued upon September 2,

19241,v to Charles L. Lee, andthe manner of I VVattaching the fins. toacylinder is'describeol` and claimed' in the copending application of iCharles F. Kettering, Serial No. 514,014, tiled November 9, 1921. f lthis specification itis-sulcient to say that these tins are attached insucha manner that -For purpose of there is substantially true thermalcontact between 'the material of the cylinder shell andthe 1ins ,.as'contrasted with a lform of. 'attachment urwhlch the i'ns' are secured tothose reached during normal operationz of' the cylinder by mechanicalineans. The

bond between the iin metal and the cylinder shell is a permanentonewhich will not deteriorate through use of thev cylinder, vand thefins will be securely fastened to the cylinder shell at temperatures inexcess `of the motor.

It has been found that by using heat dissipating ins made of copperorother material having al relatively high coefcient of heatconductivity the cooling capacity of the lateralfins is suiiicient tocool .the cylinder heads and wall-s readily and the heads are maderelatively thick to provide a large heat channel. for conducting theheat in the.

cylinder yheads readily to the lateral fins to reduce to a minimum thedifferences in temperature in the piston head and avoid the.

formation of hot spots. This construction avoids the cost and structuralcomplications l involved in forming fins on the tops of the cylinders."

, viewed iny Fig. 8, being shorter than those4 The fins are not all ofequal height, tho-se on the left-hand side of the cylinder, as

surrounding other portions of the cylinder shell and the fins on theright-hand side of the cylinder being flattened slightly. Thisarrangement of -the finning permits a close grouping -of all of thecylinders and facilitatesthe placing of the cylinders in pairs as shownin Figs. 1 and 18 with a single intake pipe or a pair of cylinders. Thisarrangement of nned cylinders is more particularly described and claimedin the. copending application of' Charles F. Kettering, Serial No.514,014, filed vlNlovembler4 9, 1921. The fin loops adjacent the holes225 are relatively short to provide a clearance for the valve push rods.As the cooling draft enters-the lower ends of the iin loops the closelygrouped tin walls act to someextent as a dust strainer or separator andremove a part of the dust carried by the air currents employed incooling. The lower ends of the fm loops are 'provided with verticalslots 238 to permit cleaning dust and other foreign material from theinside of the loops by means of a narrow brush whose bristles proectthrough the slots.

Each cylinder head 224 is provided with I intake and exhaust ports 239and 240, re-

spectively, and the inner surface ofthe cylinder head surrounding theseports is beveled as shown at 241 and 242, respectively, to provide seatsfor intake and'exhaust valves 243 and 244. Each head 224 is alsoprovided with a hole 245 for receiving a spark plug 246 and with holes247 to receive studs 248 cooperating with nuts 249,l

for securing a cylinder superstructure to a pair of cylinders.

The cyllnder superstructure designated as a Whole bv numeral`250.- (seeparticularly communicating with the intake ports of cylinders 22() and221. vr256 and 257 are exhaust conduits communicating respectively withthe exhaust ports of cylinders 220 and 221. The jointsbetweenthesuperstructure bases 251 and 252 and the cylinders 220 and 221 aresealed by kidney shaped gaskets 258 and 259. These gaskets arepreferably constructed of a material such as asbestos having a low heatconductivityto insulate the superstructure and more particularly theexhaust conduits frpm the cylinder heads and reduce the quantity of heatto be removed from the heads by the cooling fins. A large to reduce thetemperature of the exhaust pipe by the cooler fluids passing through theintake pipe. This promotes'the life of vthe valve guides and springswhich are heated by the exhaust pipe. The passages in the cylinder headsand superstructure are accurately aligned by means of short dowelsleeves 260- seatedv within counterbored recesses 261 in the cylinderhead and counter- `bored recesses 262 in the. superstructure.

Thisconstructiontholds the heads of a pair of cylinders in alignment4and promotes'rigidit-y in the structure.

Superstructure 250 is bored' to receive valve stem .guides 263 forguiding the intake and exhaust valves.- These guides' arc pressed intothe superstructure. Each valve is normally retained against its seat byav coiled spring 264 bearing at its upper .end against a spring retainerc up 265 and 'at its lower endagainsta spring rest 266. shown in Figsf15 and'16, each spring rest 266 is made of sheet metal and is providedwith three projections or feet'f`267, formed preferably by embossing.AThese fe-et space the body of each spring rest 266 and the lowerend ofa spring 264 from the upper surface of the superstructure, give a smallarea of-contact between a rest and .the superstructure and provide achannel for cooling air, thus reducing to a minimum the heat transmittedto the spring and promoting the life of the latter. The spring retainingcup 265 is heldin position by a U-washer 269 -sea-ted in a groove 270 inthe upper end Iof "mass of metal may be employed between thev l 'intakeand exhaust conduits (see Fig. 13)

the valve stem. The superstructure includes vertical irocker shaftbrackets 271 and 272 a ball portion 286 seated in a .socket formed inthe top of a push lrody cap- 287 which is f supporting a horitontalrocker shaft v273 carrying transverse .rockers 274 and 275. Each ofthese yrockers has a hub 276'carrying a suitable bushing 277 between arocker v`against washers-283 and thus yieldingly forces-adjacent innerrockers 274 and 275 against the rocker brackets 271 .and 27-2. 'Thesesprings reduce no1-se during the operation of the valve mechanism. -Eachrocker is providedat its vinner end with a foot 284- which engages theupperend vof a valve ,stem

j and the opposite end of the rocker is pro-5 vided witha `tapped holefor''receiving a screw 285 provided atjits lower end with supported by apush rod 288. Screw 285 is retained in adjusted position by nut 289.

The lower end ofpush rod 288 rests upon -a valve lifter l290 providednear its upper end with a circumferential vgroove for receiving a lwiresplit ring-291. This ring holds `the valve lifter in place in the cyl-'inder base when the valve lifter is separated from the cam shaft.- Theupper portionof guide 226 projecting above the base 222 of the cylinderis enclosedbya packing cap 292 containing a felt packing ring 293 .whichsurrounds the push rod 288. This packing ring is held 'in place by ametal washer 294 pressed intjo the cap 292.

. sipates heat rapidly.

Exhaust conduits of the lsuperstructure maybe provided with a pad 300for rev4ceiving a heat radiating member including a main plate 301preferably of copper, to whichy are attached a-series of folds 302 madef copper or other material which dis- This memberpis at-i tached 'to thepad 300 by means'of screws 303, these'pads havingvbcen previouslymachined to assist in providing a good mechanical contact between thesuperstructure and` the heat dssipating member for conducting heat'tolthe latter..

As is shown merci clearly-iu Fig. 14. the

Trecker shaft '273 is held in a fixed lposition on the super-'structureby a boltv304 having anarcuat'e'notch'305 whose curved surface ispressed against. the s'urfaceof the rocker shaft l273 by. turning the-nut 306 on the end Lof bolt"304.

ne Y

lVithin each cylinder is a piston 320.1iot

' Aherein disclosed in detaihas the same forms l vno part of theinvention Vto which this present application relates; said pistons beingconnected with the crank armsof the crank shaft 370 of. the engine,which is not described in detaihthrough 1piston rods 350.v The crankshaft is supported.l in suitable bearings by the crank case 200.4 .Thecrank Vshaft carries a pinion which meshes with a gear to thereby drivethe. ycam shaft 441' at the usual two-toone ratio; said cam shaft.being'supported in bearings carried also byA the crank case 200,andhaving cams 442 which engage the valvelifters 29,0 and thus operatethe' valves. IAn intermediate jour.

nal 443 of the cam shaft 441 has 'a pinion 444 formed therein whichmeshes lwith a gear 445 carried by the lower end of the driving shaft446 of the distributor and timer mechanism 447 which controls theignition vcircuitslof the severall cylinders. The elements and featuresherein mentioned are or may be of common or ordinary form, and needvnotbe described at length in order `that the features wherein our inventionconsists may be appreciated. l

'. oOZng system.

The timing gear housing 202 has an arm 800 (Figs. 3,4 and-19) projectinglaterally from the left-hand side of the engine, which y arm is bored`out Aat801 toreceive an annular flange 802 provided on the'frame of,generator 803.` A part of the bolts 804 which `secure the timing gearcase cover 210 .to timing gear case 202 also function to hold gencrater803 against the Vrear side of arm 800.

not be machined 4as the correct alignmentof the shaft 805 ofgenerator-803 yis provided for by the cooperation of themachined ,sur-

lIf desired thev rear surface of .arm 800 need v face 801 with themachined surface bf the and the arm 800.

. flange 802. A felt ring806 .assists insealing -the joint betweerrthegenerator frame '803,105

Shaft 805 carries generatori-gear l8074 an`d k .a fan driving pulley 808having .an adjustable flange 809 which maybe operated in a well knownmanner to tighten or loosen the fan belt '810, the belt being'preferably .of such type as will give `high'efliciency ywithout`beingdrawn taut on the pulley wheels as in prior practice, thus reducingthe pressure of the shaft journals on their bearings and thepowerrequired to drive thefan. The power required for driving the. fanis also reduced byemploying afan of the 'peripheral- .4 discharge typehaving a large intake and dis charge throat which will give. the fan alarge capacity, the air being thrown outradially at arelatively lowvelocity.

Timing gear casevcover 210 supports a vertical fan shaft `bracket811supporting, at its upper end the outer portion of fan shaftr 812whose innerend is supported by' fan spider 813. Spider 813 comprises .a'periply eral flange 814 and a hub 815 carrying the j shaft 812. The hub815' and flange 814 .aref

joined by -a plurality of lradial arms 816.

isa

(Fig. 2o) of which a part are formed with a web 817 fastened to thefront superstructure `250 by bolts 819.

' cured in operative position between the bracket 811 and the spider813. The lrear end of shaft 812 .is bored axially for a short distanceto provide an oil duct A828. An oil- ;vv

ing cup 829, attached to the rear end .of this shaft, is incommunication with this duct. Oil flows from the duct 828 through a hole830 to the bearing 823 and also down a groove 831 into the interior ofhub -821 to thel ball bearing 822. Dust excluding and oilretainingwashers 832 and 833 lare provided.I .v

Hub 821 is formed with a radialflange 834 to which are riveted fanpulley outer fia-nge 835 and fan -pulley inner flange 836. v Theseianges cooperate to provide a pulleyl driven by the belt 810. Pulleyinner fiange 836 carries fan outer wall 838 which is formed with aninwardly projecting, central, conical portion resting on the hub 821 andfunctions to deflect air toward the periphery of 'the fan. Fan outerwall 838 supports .a plurality of fan blades 839 which in turn supportfan inner wall ,840 having a rearwardly extending annular ange. 841extending within spider ange 814. Thesev fan blades are constructedpreferably ofduralumin Ato reduce the load on the belt and each blade isprovided with a plurality' of lateral ears 842 (Figs. 4 and 21) arrangedtot into suitably spaced slots in the two f an flanges. These ears arenotched in order that they may eas ily be riveted onto the outersurfaces of the fianges to hold the blades securely in position.

The draft tube shown in detail in Figs. 22 to 29, inclusive, isdesignated as a whole by numeral 850 andcomprises three principalsections 851, 852, and 853. Sections 851 and 852 have bottom walls'854and 855, re-

. spectively, which project inwardly from side walls 856 and 857,respectively. These bottom walls 854 and 855;, are scalloped as is shownin Fig. 22 to t around Ithe cylinder fins, and these bottom wallssupport skirt members 858 and 859, respectively, and have ared loweredge portions 860 and 861-. It will be noted in Figs. 2, 3, and 4, thatthese skirts 8.58 and 859 extend about half wayv down thelength of thecylinder fins. Thel wall856`of member 851 supports la fixed i.

.engine superstructure and valve -mechanism and to provide a t'ube forconducting the cooling air to the engine fan. Cover 853 is hinged at86,3l so that the cover may be f-swung'to one side as shown in Fig. 25to give access to the top portion of the engine for inspection,adjustment, and replacement of parts, should this be necessary. When inposition, the cover 853 is secured by means of buckle members 864. Atthe forward end of the draft tube 850, the parts 8 60, 862, 853, and 861, provide a substantially continnousl circular reinforcing bead whichis adapted to 'fit over the flange 814 of fan spi er 813.

- The wall 856 isprovid'ed with a-series of equally spaced holes 865.A.dowel sleeve 866 (see Fig. 12) 'passes' through each 4of 'i the holes865 and, one end of each sleeve fits within va counterbored recess 867provided .in the outer end vof each of the exhaust and inlet passagesofthe superstructure 250.

, Each ofthe sleeves 866 is adapted to vfit within a similarcounterboredrecess formedl in the outer end of each of the branchpassages of the engine manifold. This constructlon provides a mainsupport for the draft tube and fholds the superstructures in alignment.

The vmanifold comprises sections 87 O and 871. -The base portion 87 0-ofthe manifold,

which is common to both the intake and exhaust gas conduits, has anintake passage leading up from a carburetor which is bolted to theflange 874 as shown in Fig. 2.

Whenthe manifold parts are assembled,

the branch passages lofthe intake and `exhaust lmanifold will be equallyspaced and in alignment with the corresponding passages in the enginesuperstructures 250 and also with the holes 865 provided in the drafttube. A dowel-sleeve 866 (Fig. 12) may be used to connect' each of themanifold branches withabranchof an engine superstructure. vA gasketv887- is provided betweendraft tube wallg856 and the superstructure anda gasket 888 is provided between the draft tube wall and the branchportion of the manifold assembly.- A common meansv (Fig. 1) secures themanifold assembly and the draft tube portion 851 to the enginesuperstructures, and this means comprises horizontal bolts 889 supportedbyI structure, and this section in turn,y supports the section 852. Thesecti'ons'851 and 852 A are clamped together at-the ends' of the engineby clamping wedges 892 and ,893 hay# ing' upwardly converging'inturnedflanges (Figs. 26 and 27) which cooperate with com-fv plementaryoutturned flanges shown at 8.94 and 895 and carried respectively bythesklrt portions 860 and 861. Thebottomwall 8551, 10,j of section 852carries horizontalcllps 896 \whi'ch rest upontlu;` tops of the tins topro-f vide an additional supportl .for draft tube section 852. i l

The draft tube wall 855 supportsv a wire.

"conduit900 which is U-shaped 1n `4cross section :and includes sideflanges. 901 andA 902` and *a bottom` portion or web 903.` These.portions together-'With the wall 855 coop- 2O ing-from the ignitionapparatus'447 (Figs.-

crate to form va box for enclosingcable's leadland 31) vtol the variousspark plugs of the engine and also to the ignitionswitch `1of catedon'the instrument board of anvautomo bile and a conductor from thegenerator 803' 253 located aty th'e front endiof` the'engine. The

cables from the ignition apparatus enter;

l througha slot 904 in the webv 903 and the may be closed but the'rcarend is preferablyl -wire fromthe` generator enters through the hole905-. The frontend of. the conduit' 900 open to permit wires to-b'e'bought out to y such apparatus as the ignitionfcoils land 35shown). The sparkfplug cables which are the lighting and; ignitionlswitchv which are located on the'` instrument f board (not housed withinthe' conduit-T900. may each e'xtend through one of the holes-906 whichare suitably spaced to locate'the` cables 1n `a convenient' manner forattachment to the engine spa-rk plugs. The flange 901` is pros. 'videdwith al plurality of inwardly project-: .ing ears907' leachfprovidedwith a hole 908 so thatv the conduit900' may-'be attached toy the WanA Bby bolts 909 and nuts 91o.

'l As shown in Figs. 1, 4,130 ,and 31, the en# v gine is enclosed by ahood which Iincludes .a

y front section 920 fFigs. 30 and 31) and hinged side sections 921,i922, v923,;'and 924,V

ig., 4) the front section 920 beingv supportf ed by a :front crossmember 212 ofthe auto: mobile frame. 'f This fro'nt cross member 212 i'is supported by members 213 and 214 which A are secured to springbrackets 2081 and 209.

Members 213 and 214 support channel mem ^bers 9 28'and, 929' whi`ch`arefadantedv to re- .ceive the low-erlhbeadedv edges-of the hood Imembers 921 and 924. y Any suitable means Y may -be used for securingthe members `921 oov engine 4.enclosure is formed by theautomobile'dashboard 930 (Figs. 30 and'31)t which carries an inwardlyvprojecting shield 931 .l providinga pocket'for receiving the clutchandbrake pedals When pressed forward. The bottom of the"engine-enclosure is pro- -path to the fan th the tins. onthe frontcylinder.

and 9-24 in position. ',The rear wall of the vided by the oil pan-'215`itsel1 and by splash y pans 932|and 933,whic h are supportedbysidem'embers 213 and 21`4, respectively,v vand extendinwardly-toward'the engine and restv u o'n the flanges of the oilvpan215. v The front hood section 920'is provided with openings. 984. havingnarrow walls 985 inclined toward the .engine (Fig. 81)-to obscure .aview of the`parts `under the hood from a point directly in front of thelatter,

thusaddingto the appearance; of the appa-` ratus, 'The front hoodsection ,isbsimilar in front elevation to honeycomb'lradiatorsbut the`walls of ,the openingsl are relatively .narf

row' to reduce to a minimum the v`resista'n ce .to axr currentsenterlngthe hood.

y The air currents enteringthe hood in' liront of the 'fan'are deectedby the latterv .and take a 'current pathD (Fi-19) around' thefaned-gewhich curved path'conforms" generally to the reverse' pa-th'E ofthe airy thrown out by the fan'. Byl this construction the air currentsentering the hood are preventedffrom limiting the effectivedischargeopening of the fanand'a resultant cutting down'l of the fancapacity. The re` verse path taken. the exhaust air is' due chiefly tothe shape of the. fan parts. TheA general 'directionof the Jair,currents under f the hood produced by movement of' theau54 tomobile areindicated in Fig; 30 by the arrows'936and 937. The ait' currentsentering the lower portion of the` hood are prevented l*from `'passingdownwardly under 'the'.engine l bythe splash pans 932 and 933thus-avoid# ioo ing a partialvacuumjand large eddy cur.-

rents adjacent the lowerportions of the "rear 'cylinders Movementof theVehiclev creates apressure infront of theudashboard and aroundthe airinlets atgthebasesof the rear cylinders.v This pressure tends tocounterbalanc the greater fresistancedotlered by the draft tube to the`air which enters theflns on l' the rear cylinder` vandtravels'over a.greater Due to thehigh heat conductivity copper tins and the good,thermal contact of the tins withI the cylinder, the amount of coolingair employed may be varied throughout the length of the cylinder.Thisivariaan the airwhich enters rule 4 tion is produced by employing-adraft tube.-I

to air 'flow and the power requiredto drive the tan. vThis increases thecooling of the cylinder head-and decreases the cooling of f the'cylinder wall. The cooling of the cylin- 4der wall depends in part uponthe temperalture differential desired between the piston members andcool the piston skirt. The rate at which heat is removed from the pistonskirt depends on the ton head and the quantity of metal employed inconducting lieat from the piston head to the piston skirt. The bestengine performance, is obtained when the piston and cylinder heads areheated to the same temperature. Engines constructed as described havebeen successfully operated at more than 85 pounds compression on commonforms of gasoline without producing a fuel knock. The higher -thecompression at'which an engine is operated, the greater the thermalefficiency of the engine.

Due chiefly to 'thelarge' cross sectional diameter and shapeof the drafttube, the air currents pass through the latter with little if anyswirling motion thus lesseningvtlie power required' to operate thecooling. apparat-us and increasing' its efficiency.V The hotter portionof the air, which portion is drawn from over the exhaust side of theengine, is thrown outwardly by the fan away from the cooler airenteringthe`hood and passing to the intake end of the skirts surrounding thecylinders.

The quantity of air moved 'through the 'cooling system is substantiallyin direct proi ening of the draft tube skirt, may be made lsionpressures. When speed and, at constant ,substantially in the same heatgenerated when the at different speeds. This portion to engine load, thecooling is proportion to the" engine is operated gives uniform engineperformance and a better' performance at low speeds than has beenobtained beforeA in air cooled enginesi Since the fan expels the air atlow velocity,-

and since the velocity of the air after it has left thecoolingfins is oflittleiniportance,

the power lost Ain momentum of the air which has left the fan is reducedto a minimuni. Due to the more rapid heating of the engine7 when thelatter is startedv in cold weather, and to the better cooling in warmweather than is obtained in water cooled engines, the mileagev pergallon of fuel is increased and the tendency to carbonize is decreased.'The use of the air cooling meansy described Aand including thefinsl andthe means for conductingthe air over the fins gives results comparablewith the best Water cooled engines operating at high compresoperating atengine compressions in excess of BQ pounds, the engine has been operatedover long periods at speeds which give an automobile la velocity ofmiles an freezing of the pistons as is common in air cooled motors usedheretofore. The cooling So eiiiciently that variations means performssuch, for example, as a shortin construction,

temperature of thepis- ,valve stems is reduced thus prolonging the lifeof these parts. 1

' and manner of hour without a sticking or 'toproportion the coolingtothe engine con- The power unit is relatively light and compact, thepower developed is relatively high, and the construction and grouping ofthe parts gives a rigid construction adapted to modern productionmethods. The form assembling the parts reduces initial cost and cost' ofinspection and -reairs.

Vhile the form of mechanism herein shown and described, constitutes apreferred, form of embodiment of the presentinven.-

tion, "it is to be understood that other forms might be' adopted, allcoming within the `scope of the claims whiclifollow.

Vifhat we claim is as follows: l. Ina multiple cylinder internalcombusand' which superstructures are tion engine comprising a pluralityof pairs provided each with laterally extending conduitscommunicating'wi'th the ports afore said of the pair of 'cylinderswhereby it is supported; a combined inlet and exhaust. manifoldextending along and secured to the conduits aforesaid of said severalsuperstructures; and heat radiating ns arranged about the c ydlindricalportion of said cylinders and extending'downward from the plane of theheads thereof; said manifold having an inlet leading thereinto Iand anoutletleading there-v from,'and'both of which are located at one and thesame end of said manifold.

2. In a multiple cylinder internal combus- .tion engine comprising aplurality 'of pairs of cylinders all secured to and supported byajsingle crankcase and eachof which cylin ders isprovided with an inletand an exhaust port in the head thereof; a plurality of sup'erstructuresarran ed one above each pair of cy1inders,`each o saidsuperstructuresbeing provided with thkee laterally extending conduits one communicatingwith two ports one in each of the cylinders whereby it is supported, andthe other conduits communicating with the other ports in said cylinders;a draft tube extending along the heads of said cylinders and enclosingsaid super-structures, and vhaving an opening arranged adjacent saidheads; a combined intake and exhaust manifold located outside sai-ddraft tube and extending along and communicating with all the conduitsvaforesaid of said superstrucico

